Optical mechanical switches such as microelectromechanical switching devices have become increasingly used for applications for which no comparable non-mechanical electronic device is available. Even for switching applications for optical communication, telemetry, and information processing systems, for which non-mechanical electronic switching devices do exist, a need for augmented capabilities is frequently met by optical mechanical switching devices.
For both microelectromechanical switches (MEMS) and other optical mechanical switches, a need exists for monitoring and improving their performance. At present this need typically is addressed by monitoring a customer's signals traveling through the system. Since a customer's signals frequently have a very large dynamic range, this technique requires the use of detectors with a dynamic range at least as large. A further drawback is that this technique requires a customer's signals to be present. Such signals are available only after a cross-connect has been provided. If the service provider chooses to modulate the customer's signals to ease design of the detection circuit, other problems, such as noise, result. Even the DC signals used by some providers are susceptible to, and may cause, noise.
Accordingly, improved monitoring techniques are urgently needed.